It's hard to imagine that when they were new, they were all covered with smooth marble that has long since been carried off. There are so many pyramids that didn't survive their own engineering and collapsed in on themselves too, now buried deeply under the sands. We missed out seeing a lot of amazing sights simply because we were born too late...

It's hard to imagine that when they were new, they were all covered with smooth marble that has long since been carried off. There are so many pyramids that didn't survive their own engineering and collapsed in on themselves too, now buried deeply under the sands. We missed out seeing a lot of amazing sights simply because we were born too late...

Stitchawl

But if we had been born then, we'd have probably died building one of them...

I'm sure you get the gist, but girding your loins according to Wikipedia means:

"The term "gird one's loins" was used in the Roman Era meaning to pull up and tie one's lower garments between one's legs to increase one's mobility in battle. In the modern age, it has become an idiom meaning to prepare oneself for the worst."

So I guess Stitchy was right . Although these days it tends to be used colloquially just to say that you are getting ready to go/leave.